Tread pattern duplicating machine

ABSTRACT

A machine for cutting a tread design, or a series of configured grooves in a molded blank tread of a tire. A precast or molded pattern with a predetermined tread design, and a tire with a blank tread are mounted on the machine for unitary rotation in parallel planes. The machine has a sensor and cutter which are mounted in corresponding spaced relation from the pattern and tire, respectively. The cutter moves in cutting relation with the blank tread in corresponding relation to movement of the sensor over the pattern, such that the tread design on the molded pattern is duplicated on the tread of the tire.

United States Patent [72] Inventors Christopher E. Christie 2,939,5206/1960 Frohlich et al l57/l3 on, 01110; 3,354,929 ll/l967 French 157/13William J. Head, Rolllngen, Luxembourg 3,502,13 l 3/1970 Rawls l57/ l 3l PP 561564 Primary ExaminerGranville Y. Custer, In 5} filled d isA!rneysF. W. Brunner and Harlan E. Hummer [4 atente ov. [73] AssigneeThe Goodyear Tire & Rubber Company Akron, Ohio ABSTRACT: A machine forcutting a tread design, or a series of configured grooves in a moldedblank tread of a tire. A precast or molded pattern with a predeterminedtread design, TREAP PATTERI? DUFHICATING MACHINE and a tire with a blanktread are mounted on the machine for 14 Chums 7 Drawmg Flgs' unitaryrotation in parallel planes. The machine has a sensor [52] US. Cl 157/13and cutter which are mounted in corresponding spaced rela- B29h 17/40tion from the attern and tire, res ectivel The cutter moves [5]] Int.Cl.P P y Field of Search l57/l3 in cuttmg relation with the blank tread incorresponding relation to movement of the sensor over the pattern, suchthat the [56] References Cl'ed tread design on the molded pattern isduplicated on the tread UNITED STATES PATENTS of the tire.

l,52l,238 12/1924 Gammeter 157/13 :1: A; 6O 10 a a 57 I 1 1 63 5 l 36 II I4 36 I: 69 1i E 5 22 6| 76 77 82 g, 1 7 '83 '1 64 1 l 77 1 1 12 1 1'11 7s 810 EM 1 1 I. 82 1 1 1/ 1 1 1 k l 25 "{11*11: '5 1 I 1'111/ 1 R 515& I 5o 36 '1 '1 l l L" II F fix-L1 ,11"\ 41 l/ 1} 1 -5 i [i/fi l l 1 1411 1 1 13 -11" 9 l l 22 11 7 11 1' *1 1 1 5&7 1'42 45 49 1 e 1 4'1 FFIRE} 7--5QT 1 39 1' 1 I JI :F- 11% E T. i i l I 9 I5 38 A l i It 20 Hl: 22 I I 1 I I J 11 l5 i y I L I 14 7| SHEET 2 [IF 5 PATENTEDNUV 30I973 -M v Q hp- Hr 1. D, j mm m Wm 1 mm 1 I 1 I I I I I 1 1 l i Il 0 M Qg 0 mm v //Vl E/V70f?5 CHRISTOPHER E. CHRISTIE WILLIAM J. HEAD ATTORNEYPATENTEBN 3 0 9 SHEET .3 BF 5 WILLIAM J. HEAD CHRISTOPHER E. CHRISTIEATTORNEY PATENTE'UNnv 30 I871 SHEET U [1F 5 I/VVE/VTOHS CHRISTOPHER E.CHRISTIE WILLIAM J. HEAD ATTORNEY PATENTE-DHGV 30 i9" 3 823 531 SHEET 5BF 5 [N70 5 CHRISTOPHER E. CHRISTIE WILLIAM J. HEAD ATTORNEY BACKGROUNDOF THE INVENTION The invention is particularly well suited for cuttingexperimental tread designs in tires, especially large tractor andearthmoving tires. Generally, special molds must be designed and builtfor every new experimental tread design. These molds are costly,especially since they may only be used once. Moreover, it usually takesanywhere from 6 months to a year to obtain a special mold for buildingsuch tires. This is very time consuming and oftentimes experimentalprojects are unduly delayed and even abandoned, because a mold is notreadily available for producing the desired tire.

The invention is directed to providing a machine wherein a new treaddesign can be easily duplicated on tires whose tread has been molded inblank, i.e., the molds are smooth and not provided with grooves andserrations for forming any particular tread pattern. Such a machine ishighly beneficial from a molding standpoint since a single mold can beused for producing a number of tires with different tread designs.

Briefly stated, the invention is in a machine for cutting apredetermined tread design in a tire. Means are provided for mounting arubber tire with a blank tread and a molded segment or pattern of a tirewith a predetermined tread design, for unitary rotation through apredetermined arc. A sensor is mounted adjacent the tire pattern forcontact gliding relation over the predetermined tread design formed inthe pattern. A cutter is mounted adjacent the rubber tire for engagingand cutting a design in the blank tread similar to that of the pattern.Means are provided for moving the cutter in cutting relation with theblank tread of the tire in corresponding relation to contacting movementof the sensor over the predetermined tread design of the pattern.

DESCRIPTION OF THE DRAWING The following description of the inventionwill be better understood by having reference to the annexed drawing,wherein:

FIG. 1 is a plan view of a machine made in accordance with theinvention;

FIG. 2 is a front view of the machine;

FIG. 3 is a right side view of the machine;

FIG. 4 is a left side view of the machine;

FIG. 5 is a section of the machine viewed from the line 55 of FIG. 1;

FIG. 6 is a section of the machine viewed from the line 6-6 of FIG. I;and

FIG. 7 is a schematic drawing of the mechanism for monitoring andcoordinating movement of the sensor and cutter head of the machine.

DESCRIPTION OF THE INVENTION Referring, generally, to the drawing and,more particularly, to FIGS. 1-4, there is shown a machine, generallyindicated at 8, for duplicating a predetermined tread design in a moldedblank tread of a tire, especially large tractor or earthmoving pneumatictires. The tread-duplicating machine 8 comprises an upstanding machinebase or frame 9 on which a set of guide rails 10, 11, and 12, and a pairof guide rods 13 and 14 are all mounted in parallel relation.

A platform 15 is mounted on pairs of angularly disposed rollers 16 and17, which rollingly engage the guide rails -12. A pair of brackets 18and 19 (FIG. 4) extend from the platform for coupling and slidingengagement along each of the guide rods 13 and 14 to stabilize theplatform 15.

A drive screw 20 is mounted on the machine base 9 in parallel relationto the guide rails 10-12, and coupled to the platform 15. Ahand-operated crank or wheel 21 is secured to the drivescrew 20 and usedto operate or rotate the drivescrew 20 to reciprocate the platform 15along the guide rails 10-12 and guide rods 13 and 14. A number ofexpansible bellows 22 are provided for protecting and keeping debrisfrom falling on the guide rods 13 and 14 and hampering movement of theplatform 15.

A pair of arcuate, preferably circular, trackways 25 and 26 are can'iedby the platform 15 in spaced side-by-side relation. Each of thetrackways 25 and 26 (FIG. 5) are U-shaped having a pair of upstandingcurved parallel sides 27 and 28, which are integrally formed with a base29 secured to the platform 15. An arcuate recess 30 is formed betweenthe upstanding sides 27 and 28 and base portion 29 of the trackways 25and 26. A series of rectangularly spaced rollers 31, 32, 33, and 34extend into the, recess 30 in spaced relation along the trackways 25 and26.

An inverted U-shaped arcuate mover 35 is movable along each trackway 25and 26 in guided, rolling engagement between the rollers 31-34. Similarexpansible bellows 36 (FIG. 1) are provided for preventing debris fromfalling into the recess 13 and hampering movement of the movers 35 alongtheir respective trackways.

A manually rotated crank or wheel 38 is used for operating or moving themovers 35 in unitary corresponding relation along their respectivetrackways 25 and 26. A gear 39 (FIGS. 1 and 6), coupled to the handcrank38, is in meshing driving relation with a conventionally designed spurgear 40 which, in turn, is keyed for unitary rotational movement withdrive shaft 41, A smaller pinion 42 is keyed to the drive shaft 41 inspaced relation below the Boston gear 40. The pinion 42 is in meshingdriving relation with gear teeth, e.g., tooth 43 (FIG. 5), disposedalong the outer periphery 44 of the mover 35 in the adjacent trackway26.

A sprocket wheel 45 is keyed to the drive shaft 41 and coupled by achain belt 46 to a similar sprocket wheel 47 associated with the othermover 35 and trackway 25. The sprocket wheel 47 is similarly keyed to adrive shaft 48 for operating or rotating a pinion 49, which is inmeshing driving engagement with gear teeth disposed along the outerperiphery of the other mover 35 in the trackway 25. Thus, the movers 35are correspondingly moved in unison along their respective trackways 25and 26.

A cutting assembly 50 and sensor assembly 51 are mounted on the movers35 in the trackways 25 and 26, respectively. These two assemblies willbe described in greater detail after the following cooperatingmechanisms have been explained.

A support bar 54 is journaled for rotation in a set of pillow blocks 55,56, and 57, which are secured in aligned, spaced relation to anupstanding frame portion 58 of the machine base 9. The support bar 54 isdisposed above the platform 15 and rotates about an axis which isparallel to the plane of the platform 15 and transversely disposed tothe axes of the guide rails 10-12 and guide rods 13 and 14.

A conventionally designed indexing plate or ring 59 is mounted on theend 60 of the support bar 54 protruding or extending beyond the pillowblock 55 adjacent the trackway 25. A tractor tire 61 with a molded blanktread 62, for example, is placed on a conventional wheel rim andinflated to a normal operating pressure. The tractor tire 61 is thenmounted on the indexing plate 59 for rotation in a plane normal to thelongitudinal axis of the support bar 54. The tractor tire 61, whenmounted, extends towards the adjacent arcuate trackway 25. The carcassof the tire 61 in the area of the tread, assumes a generally circularconfiguration when inflated, having a simple radius R and center pointCP. The handcrank 21 is used to move the platform 15 and trackways 25and 26 towards the support bar 54, until the center point of the arcuatetrackway 25 coincides with the center point CP of the tractor tire 61.

A support arm 63 (FIG. 1) is keyed to the support bar 54 intermediatethe pillow blocks 56 and 57 and extends laterally towards the adjacenttrackway 26. A pattern 64 with a predetennined tread design 65, ismounted on the free end 66 of the support arm 63. The pattern 64 is anarcuate segment which is cast or molded from any suitable material,e.g., plastic or plaster. The support arm 63 and pattern 64 can beintegrally cast and mounted on the support bar 54.

A lever arm 67 (FIG. 4) is keyed to, and extends from the support bar 54in a direction towards the platform 15. The free end 68 of the lever arm67 is slidably mounted for limited vertical movement on a coupler 69which threadably engages a drive rod 70 mounted on the machine base 9 inparallel relation to the guide rails 10-12. A handcrank 71 is providedfor rotating the drive rod 70 to move the coupler 69 and consequentlyrotate the lever 67 which, in turn, rotates the tractor tire 61 andpattern 64 in unison through a corresponding are which, at most, isequivalent, in degrees, to the pitch of the tread, i.e., the frequencywhich the tread design repeats itself around the circumference or treadof the tire. For example, if the tread design is repeated 10 times, thepitch would be 10 and the corresponding arc would be one-tenth of 360 or36. The lever arm 67 is designed to rotate through a maximum arc ofabout 40, which accommodates most of the tractor tires presently beingbuilt.

CUTTING AND SENSOR ASSEMBLIES The cutting and sensor assemblies 50 and51 (FIG. 2) each comprise a guide 76, which is secured to the movers 35in transverse radial relation to the circular centerline of the arcuatetrackways and 26. A carriage 77 is slidably mounted on each guide 76 formovement towards and away from the tractor tire 61 and tread pattern 64.A hydraulic cylinder 78 is coupled between each guide 76 and carriage 77for reciprocating the carriage 77 along the guide 76.

An air or electric motor 79 is mounted on the movable carriage 77 of thecutting assembly 50. A cutter or cutting head 80 extends from the airmotor 79 and rotates about an axis parallel to the shaft of the airmotor 79. The cutter 80 is an end mill type cutter with two lips orcutting edges for cutting laterally and axially like a drill or auger incutting rubber from the blank tread 62 of the tractor tire 61.

A conventionally designed mechanical servo-valve 81 is mounted on thecarriage 77 of the sensor assembly 51. A sensor 82 is associated withthe servo-valve 81 and biased by a coil spring (not shown) outwardlyfrom the valve 81 for riding or gliding engagement over the tread design65 formed in the pattern 64. The tracing extremity 83 of the sensor 82and the cutter 80 are correspondingly configured to make: the cuttingmore exact. The hydraulic cylinder 78 is designed to retract thecarriage 77 and sensor 82, when a force exceeding a predetermined forceacts against the sensor 82 in any direction (see dotted positions inFIG. 1), including an axial direction. The cutting and sensor assemblies50 and 51 are in electrical communication such that the cutter 80 movesin corresponding relation to movement of the sensor 82 as it traces ormoves along the recesses and ridges of the predetermined tread design 65of the pattern 64.

The position of the piston within the hydraulic cylinder 78 of thesensing assembly 51, is sensed or monitored by a conventionally designedpotentiometer 84 (FIG. 7) associated with the hydraulic cylinder 78. Anelectrical input signal from the potentiometer 84 of the cuttingassembly 50, also transmits an input signal to the servocontrol unit 85,which monitors and compares both input signals. The input signal fromthe potentiometer 86 will be in lagging relation to the input signalfrom potentiometer 84, if there is any difference between the signals.

The servocontrol unit 85 is designed to transmit an output signal incorresponding relation to the difierence between the valve 87 to adjustthe position of the cutter 80 so that it corresponds to the position ofthe sensor 82. This electrical device is especially useful forretracting the cutter 80 immediately to keep it from gouging or makingan erroneous cut in the blank tread 82 of the tractor tire 61, when thecarriage 77 of the sensor assembly 51 retracts in response to apredetermined force on the sensor 82.

In operation, the tractor tire 61 is placed on a rim, inflated to anormal operating pressure and mounted on the indexing plate 59. Theplastic tire pattern 64 is mounted for unitary rotational movement withthe tractor tire 61. The platform 15 is then adjusted or moved such thatthe center point of the arcuate trackway 25 coincides with the centerpoint CP of the radius R of the tractor tire carcass adjacent the tread.The cutting and sensor assemblies 50 and 51 are in the position shown inFIG. 1 and are moved laterally across the tire, or radially relative toa plane passing through the midcircumferential centerline of the tractortread, by rotating the crank 38. A second lateral pass is made after thecrank 71 is rotated to simultaneously arcuately reposition the tractortire 61 and pattern 64. It has been found desirable to cut only one-halfof the tire at a time, after which the tire and pattern 64 are reversedto complete cutting the tread. The tread design is cut circumferentiallyaround one-half of the blank tread 62 of the tractor tire 61, before thepattern 64 and tire 61 are changed.

Thus there has been described a new and novel machine for duplicating atread pattern in a molded blank tread of a tire. The machine isprimarily designed for cutting heavier treads used in tires for tractorsor other types of off-the-road equipment. It is conceivable, however,that using smaller sensors and cutters, the invention could be madeapplicable for cutting smaller tread grooves or recesses in passengerand smaller truck tires.

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

What is claimed is:

1. A machine for cutting a tread design in a tire, comprising:

a. means for mounting a pattern with a preformed tread design, forrotation through a predetermined arc;

b. means for mounting a tire with a blank tread, for corresponding,unitary rotation with the pattern;

c. a sensor for contact, gliding relation over the tread design of thepattern;

d. a cutter for engaging and cutting a tread design in the blank tread;and

e. means for moving the cutter in cutting relation with the blank treadin corresponding relation to contacting movement of the sensor over thetread design of the pattern.

2. The machine of claim 1, which includes:

f. a pair of arcuate trackways along which the sensor and cutter move;and

g. means for mounting the trackways for unitary movement towards andaway from a pattern and tire mounted on the machine.

3. The machine of claim 2, wherein the pattern and tire are mounted forrotation in parallel planes.

4. The machine of claim 2, which includes:

h. means for moving the sensor and cutter in unison along the trackwaysto laterally position the sensor and cutter relative to a plane passingthrough the midcircumferential centerline of the tread design of thepattern and blank tread of the tire.

5. The machine ofclaim 1, which includes:

i. means for biasing the sensor against the tread design of the pattern.

6. The machine of claim 5, which includes:

j. means for retracting the sensor from the pattern when a force exertedagainst the sensor exceeds a predetermined force for which the sensor isset to retract.

7. The machine of claim 1, which includes:

k. a mechanism for sensing corresponding movement of the cutter relativeto the sensor; and

in means for adjusting movement of the cutter to bring said movementinto corresponding relation with movement of the sensor, when movementof the cutter lags behind corresponding movement of the sensor.

8. The machine of claim 1, wherein the center point of the arcuatetrackway of the cutter is generally coincidental with the center pointof the radius of the tire carcass before the machine is operated.

9. A machine for cutting a tread design in a tire, comprising:

a. a machine base;

b. a pair of arcuate trackways horizontally disposed in sideby-sidespaced relation on the machine base;

c. means for mounting a pattern with a preformed tread design, forrotation in a vertical plane and through a predetermined arc;

cl. means for mounting a tire with a blank tread, for rotation in unisonwith the pattern and in a plane parallel to the plane of rotation of thepattern;

e. means for moving the trackways in unison to positions where theypartially surround the pattern and tire;

f. a sensor for contact, gliding relation over the tread design of thepattern;

g. a cutter for engaging and cutting a tread design in the blank tread;

h. means for mounting the sensor for movement along the trackwayadjacent the pattern;

i. means for mounting the cutter for movement along the trackwayadjacent the tire;

j. means for coupling the sensor and cutter together for unitarymovement along the trackways;

k. means for biasing the sensor against the tread design of the pattern;

m. means for retracting the sensor from the pattern when a force exertedagainst the sensor exceeds a predetermined force for which the sensor isset to retract; and

n. means for moving the cutter in cutting relation with the blank treadof the tire in corresponding relation to movement of the sensor incontacting relation over the tread design of the pattern.

10. The machine of claim 9, which includes:

0. a mechanism for sensing corresponding movement of the cutter relativeto the sensor; and

p. means for adjusting movement of the cutter to bring said movementinto corresponding relation with corresponding previous movement of thesensor, if movement of the cutter is lagging behind movement of thesensor.

11. The machine of claim 10, wherein the center point of the arcuatetrackway of the cutter is generally coincidental with the center pointof the radius of the tire carcass adjacent the blank tread before themachine is operated.

12. The machine of claim 11, wherein the sensor and cutter extend in atransverse radial direction relative to the circular centerline of theirrespective trackways.

13. A method of cutting a tread design in a tire, comprising the stepof:

a. moving a cutter in tread-cutting relation with a blank tire tread incorresponding relation to contacting movement of a sensor over a treaddesign disposed in a preformed pattern.

14. The method of claim 13, which includes:

bl retracting the cutter from the tire tread in response to apredetermined force on the sensor.

l 0 l t

1. A machine for cutting a tread design in a tire, comprising: a. meansfor mounting a pattern with a preformed tread design, for rotationthrough a predetermined arc; b. means for mounting a tire with a blanktread, for corresponding, unitary rotation with the pattern; c. a sensorfor contact, gliding relation over the tread design of the pattern; d. acutter for engaging and cutting a tread design in the blank tread; ande. means for moving the cutter in cutting relation with the blank treadin corresponding relation to contacting movement of the sensor over thetread design of the pattern.
 2. The machine of claim 1, which includes:f. a pair of arcuate trackways along which the sensor and cutter move;and g. means for mounting the trackways for unitary movement towards andaway from a pattern and tire mounted on the machine.
 3. The machine ofclaim 2, wherein the pattern and tire are mounted for rotation inparallel planes.
 4. The machine of claim 2, which includes: h. means formoving the sensor and cutter in unison along the trackways to laterallyposition the sensor and cutter relative to a plane passing through themidcircumferential centerline of the tread design of the pattern andblank tread of the tire.
 5. The machine of claim 1, which includes: i.means for biasing the sensor against the tread design of the pattern. 6.The machine of claim 5, which includes: j. means for retracting thesensor from the pattern when a force exerted against the sensor exceedsa predetermined force for which the sensor is set to retract.
 7. Themachine of claim 1, which includes: k. a mechanism for sensingcorresponding movement of the cutter relative to the sensor; and m.means for adjusting movement of the cutter to bring said movement intocorresponding relation with movement of the sensor, when movement of thecutter lags behind corresponding movement of the sensor.
 8. The machineof claim 1, wherein the center point of the arcuate trackway of thecutter is generally coincidental with the center point of the radius ofthe tire carcass before the machine is operated.
 9. A machine forcutting a tread design in a tire, comprising: a. a machine base; b. apair of arcuate trackways horizontally disposed in side-by-side spacedrelation on the machine base; c. means for mounting a pattern with apreformed tread design, for rotation in a vertical plane and through apredetermined arc; d. means for mounting a tire with a blank tread, forrotation in unison with the pattern and in a plane parallel to the planeof rotation of the pattern; e. means for moving the trackways in unisonto positions where they partially surround the pattern and tire; f. asensor for contact, gliding relation over the tread design of thepattern; g. a cutter for engaging and cutting a tread design in theblank tread; h. means for mounting the sensor for movement along thetrackway adjacent the pattern; i. means for mounting the cutter formovement along the trackway adjacent the tire; j. means for coupling thesensor and cutter together for unitary movement along the trackways; k.means for biasing the sensor against the tread design of the pattern; m.means for retracting the sensor from the pattern when a force exertedagainst the sensor exceeds a predetermined force for which the sensor isset to retract; and n. means for moving the cutter in cutting relationwith the blank tread of the tire in corresponding relation to movementof the sensor in contacting relation over the tread design of thepattern.
 10. The machine of claim 9, which includes: o. a mechanism forsensing corresponding movement of the cutter relative to the sensor; andp. means for adjusting movement of the cutter to bring said movementinto corresponding relation with corresponding previous movement of thesensor, if movement of the cutter is lagging behind movement of thesensor.
 11. The machine of claim 10, wherein the center point of thearcuate trackway of the cutter is generally coincidental with the centerpoint of the radius of the tire carcass adjacent the blank tread beforethe machine is operated.
 12. The machine of claim 11, wherein the sensorand cutter extend in a transverse radial direction relative to thecircular centerline of their respective trackways.
 13. A method ofcutting a tread design in a tire, comprising the step of: a. moving acutter in tread-cutting relation with a blank tire tread incorresponding relation to contacting movement of a sensor over a treaddesign disposed in a preformed pattern.
 14. The method of claim 13,which includes: b. retracting the cutter from the tiRe tread in responseto a predetermined force on the sensor.